The present invention relates to methods and apparatus for handling articles, such as pieces of timber, of different types.
Thus, the present invention relates to a method and apparatus for sorting articles such as sawed timber pieces of different qualities and/or lengths, in such a way that a relatively large number of consecutive sorting compartments are utilized with the articles of given types situated in these compartments to be transferred therefrom, primarily by gravity, onto a conveyer situated below the compartments, this conveyer delivering the articles to a location where the articles are treated as by being packaged, with the articles being delivered to the conveyer after the compartments are filled. The transfer of the articles from the compartments to the conveyer situated therebeneath is preferably carried out by way of yieldable bottom closures for the compartments which can be controlled so as to open and close the compartments, these closures for example taking the form of walls which are hinged at one side to each compartment so as to be swingable to and from positions closing and opening the compartment.
It is already known in connection with sorting of sawed pieces of timber to utilize installations having an overhead conveyer provided with supports for carrying pieces of timber and including a triggering means which can be actuated so that the sawed pieces of timber are released from the conveyer to drop into certain compartments situated beneath the overhead conveyer. These compartments may be made up of a relatively large number of consecutive compartments arranged in a row, these compartments numbering several tens of compartments, with at least one compartment being provided for a given type and/or quality of timber pieces. Each compartment has a bottom which can be opened and through which a batch of timber accumulated within the compartment is dropped primarily by gravity onto a conveyer situated beneath the compartment, this conveyer transporting the timber batches to a mechanism which meters the timber pieces to a packaging device, for example. Thus, the structure which receives the articles from the conveyer beneath the compartments treats the articles one by one so as to arrange them in a continuous layer which is fed to suitable packaging equipment.
The above-mentioned triggering structure for the overhead conveyer receives a pulse under the control of an individual who works at a sorting table or console situated in the region of the installation, or an automatic device may be provided for automatically triggering the release of the articles to drop into a particular compartment at the exact moment when the particular article is situated above the compartment intended to receive the same. Thus in this way the pieces of sawed timber will be dropped into the correct compartments.
It is also known to provide various sorting chambers which operate according to an elevator principle, the bottom of such chambers descending automatically as the compartment fills. The advantages of this type of compartment which operates according to the elevator principle is that there is only a relatively small height through which the articles drop from the overhead conveyer into the compartment. On the other hand, such compartments have an exceedingly complex construction and are expensive. However, it has frequently been considered proper to utilize sorting compartments operating according to the elevator principle when very large compartments are utilized.
Both in connection with stationary and elevator types of compartments, the opening and closing at the bottom ends thereof has in recent times generally been arranged to take place, for example, in a manner disclosed in Finnish Pat. No. 44,352, utilizing compartment bottoms which are swingably hinged at one side and which are opened in a controlled manner by way of hydraulic cylinders or the like, actuating structure such as ropes or reels, utilized so as to render the bottoms yieldable in an upward direction.
Modern sorting installations of the above general type have a high capacity. Thus, such installations are capable of handling more than 100 pieces per minute. Thus, the operations in connection with emptying of the compartments and subsequent transport of the articles to devices such as packaging devices has become an important factor. This factor frequently forms a bottleneck which determines the capacity of the entire sorting installation. One of the reasons for this latter condition resides in the fact that in particular in Nordic countries procedures in recent times have generally been adopted for sorting articles such as timber pieces according to length and tying all of the pieces of a given length into a package which itself is composed of a plurality of smaller packages, such as, for example, four smaller packages each of which has articles of identical lengths or quality, and these subsidiary packages are tied into a single package. The quantity of timber which is required to make up one of the smaller subsidiary packages is quickly gathered in a sorting compartment, so that it is necessary that such a compartment should be emptied and its contents transferred to the packaging operation in a rapid manner. Sorting compartments of even a relatively large size have been provided in such a way that they can accommodate, for example, sawed timber pieces for making four small packages. Experience has shown, however, that it is exceedingly awkward to transfer such a large quantity of timber to the conveyer therebeneath in a controlled manner. In particular it is difficult to arrange a relatively large heap of timber pieces so that they will form, piece by piece, a layer suitable for packaging purposes. It is particularly in connection with this latter phase of the operation, involving arranging of the timber pieces in a uniform layer, which results in damage to the timber pieces and in troubles in connection with the operation of the equipment, particularly where relatively large compartments are utilized.
Thus, it is highly desirable to provide an arrangement according to which the articles such as timber pieces when discharged onto the conveyer therebeneath can be made to assume the shape of a uniform layer of relatively small depth, with the pieces of timber retaining their proper succession and orientation. In this way it is possible to facilitate the further transport of the timber pieces and the proper handling thereof for packaging purposes. However up to the present time these objectives have not been met by known procedures and installations.
It is to be noted that the operations in connection with emptying consecutive compartments in a sorting installation have also been rendered difficult as a result of the fact that the sorting section is quite long, including several tens of compartments, this situation also being complicated by the fact that a number of compartments may become filled almost simultaneously, so that they should be rapidly emptied and ready to receive the next pieces of timber which arrive at the overhead conveyer. Thus, one of the drawbacks encountered with presently known installations resides in the fact that even though there is automation, nevertheless the supervision of a long sorting installation with dozens of compartments requires an operator to be on hand at a suitable location.